tcp: enforce tcp_min_snd_mss in tcp_mtu_probing()

[pandora-kernel.git] / mm / migrate.c

diff --git a/mm/migrate.c b/mm/migrate.c
index 180d97f..3f95bab 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -34,6 +34,7 @@
 #include <linux/syscalls.h>
 #include <linux/hugetlb.h>
 #include <linux/gfp.h>
+#include <linux/ptrace.h>
 
 #include <asm/tlbflush.h>
 
@@ -141,13 +142,16 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma,
 
        get_page(new);
        pte = pte_mkold(mk_pte(new, vma->vm_page_prot));
+
+       /* Recheck VMA as permissions can change since migration started  */
        if (is_write_migration_entry(entry))
-               pte = pte_mkwrite(pte);
+               pte = maybe_mkwrite(pte, vma);
+
 #ifdef CONFIG_HUGETLB_PAGE
        if (PageHuge(new))
                pte = pte_mkhuge(pte);
 #endif
-       flush_cache_page(vma, addr, pte_pfn(pte));
+       flush_dcache_page(new);
        set_pte_at(mm, addr, ptep, pte);
 
        if (PageHuge(new)) {
@@ -184,15 +188,14 @@ static void remove_migration_ptes(struct page *old, struct page *new)
  *
  * This function is called from do_swap_page().
  */
-void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
-                               unsigned long address)
+static void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
+                               spinlock_t *ptl)
 {
-       pte_t *ptep, pte;
-       spinlock_t *ptl;
+       pte_t pte;
        swp_entry_t entry;
        struct page *page;
 
-       ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
+       spin_lock(ptl);
        pte = *ptep;
        if (!is_swap_pte(pte))
                goto out;
@@ -220,6 +223,20 @@ out:
        pte_unmap_unlock(ptep, ptl);
 }
 
+void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
+                               unsigned long address)
+{
+       spinlock_t *ptl = pte_lockptr(mm, pmd);
+       pte_t *ptep = pte_offset_map(pmd, address);
+       __migration_entry_wait(mm, ptep, ptl);
+}
+
+void migration_entry_wait_huge(struct mm_struct *mm, pte_t *pte)
+{
+       spinlock_t *ptl = &(mm)->page_table_lock;
+       __migration_entry_wait(mm, pte, ptl);
+}
+
 #ifdef CONFIG_BLOCK
 /* Returns true if all buffers are successfully locked */
 static bool buffer_migrate_lock_buffers(struct buffer_head *head,
@@ -278,7 +295,7 @@ static inline bool buffer_migrate_lock_buffers(struct buffer_head *head,
  * 2 for pages with a mapping
  * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
  */
-static int migrate_page_move_mapping(struct address_space *mapping,
+int migrate_page_move_mapping(struct address_space *mapping,
                struct page *newpage, struct page *page,
                struct buffer_head *head, enum migrate_mode mode)
 {
@@ -361,6 +378,7 @@ static int migrate_page_move_mapping(struct address_space *mapping,
 
        return 0;
 }
+EXPORT_SYMBOL(migrate_page_move_mapping);
 
 /*
  * The expected number of remaining references is the same as that
@@ -460,6 +478,7 @@ void migrate_page_copy(struct page *newpage, struct page *page)
        if (PageWriteback(newpage))
                end_page_writeback(newpage);
 }
+EXPORT_SYMBOL(migrate_page_copy);
 
 /************************************************************
  *                    Migration functions
@@ -1180,20 +1199,17 @@ set_status:
  * Migrate an array of page address onto an array of nodes and fill
  * the corresponding array of status.
  */
-static int do_pages_move(struct mm_struct *mm, struct task_struct *task,
+static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
                         unsigned long nr_pages,
                         const void __user * __user *pages,
                         const int __user *nodes,
                         int __user *status, int flags)
 {
        struct page_to_node *pm;
-       nodemask_t task_nodes;
        unsigned long chunk_nr_pages;
        unsigned long chunk_start;
        int err;
 
-       task_nodes = cpuset_mems_allowed(task);
-
        err = -ENOMEM;
        pm = (struct page_to_node *)__get_free_page(GFP_KERNEL);
        if (!pm)
@@ -1351,10 +1367,10 @@ SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
                const int __user *, nodes,
                int __user *, status, int, flags)
 {
-       const struct cred *cred = current_cred(), *tcred;
        struct task_struct *task;
        struct mm_struct *mm;
        int err;
+       nodemask_t task_nodes;
 
        /* Check flags */
        if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
@@ -1370,23 +1386,13 @@ SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
                rcu_read_unlock();
                return -ESRCH;
        }
-       mm = get_task_mm(task);
-       rcu_read_unlock();
-
-       if (!mm)
-               return -EINVAL;
+       get_task_struct(task);
 
        /*
         * Check if this process has the right to modify the specified
-        * process. The right exists if the process has administrative
-        * capabilities, superuser privileges or the same
-        * userid as the target process.
+        * process. Use the regular "ptrace_may_access()" checks.
         */
-       rcu_read_lock();
-       tcred = __task_cred(task);
-       if (cred->euid != tcred->suid && cred->euid != tcred->uid &&
-           cred->uid  != tcred->suid && cred->uid  != tcred->uid &&
-           !capable(CAP_SYS_NICE)) {
+       if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) {
                rcu_read_unlock();
                err = -EPERM;
                goto out;
@@ -1397,16 +1403,25 @@ SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
        if (err)
                goto out;
 
-       if (nodes) {
-               err = do_pages_move(mm, task, nr_pages, pages, nodes, status,
-                                   flags);
-       } else {
+       task_nodes = cpuset_mems_allowed(task);
+       mm = get_task_mm(task);
+       put_task_struct(task);
+
+       if (!mm)
+               return -EINVAL;
+
+       if (nodes)
+               err = do_pages_move(mm, task_nodes, nr_pages, pages,
+                                   nodes, status, flags);
+       else
                err = do_pages_stat(mm, nr_pages, pages, status);
-       }
 
-out:
        mmput(mm);
        return err;
+
+out:
+       put_task_struct(task);
+       return err;
 }
 
 /*